1. Field of the Invention
The invention pertains to a cable as suspension means for lifts or elevators, which is connected with an elevator car or a load-receiving means, wherein the cable consists of synthetic fibers.
2. Discussion of the Background of the Invention and Material Information
Until recently, steel cables were used in elevator construction, which cables are connected with the elevator cars or the load-receiving means and counterweights, in the simplest case in the ration of 1:1. The use of steel cables, however, entails some disadvantages. Due to the high inherent weight of the steel cable, limits exist with respect to the lifting height of an elevator installation. Furthermore, the co-efficient of friction or frictional value between the metallic drive pulley and the steel cable is so low that the frictional value must be increased by different measures, such as special groove shapes or special groove linings in the drive pulley, or through an increase of the loop angle. Beyond that, the steel cable acts as a sound bridge between the drive and the elevator car, which entails a reduction in travelling comfort. In order to reduce these undesired effects, expensive constructional measures are required. Moreover, steel cables in comparison with the synthetic fiber cables, can absorb a lower number of bending cycles, are exposed to corrosion and must be regularly maintained.
An inlay ring for lining the wire cable grooves of cable rollers for cable railways and elevators, wherein the inlay ring consists of an elastic material for the damping of noises and for the preservation of the wire cables, is set forth in Swiss Patent Publication CH-PS 495 911. In order to assure better removal of the internal heat, the inlay ring is built up of several individual segments spaced from one another. The expansion of the inlay ring, which takes place as a consequence of heating, is compensated for by spacings between the individual segments. Upon loading of the wire cable, the elastic material can deviate or yield into the adjacent incisions and is thereby relieved to a certain extent so that no tears occur in the cable groove. In the case of localized wear of the inlay ring, individual segments must be replaced.
In the previously invention, a steel cable is still used as suspension means, with the steel cable still displaying the initially-mentioned disadvantages. Furthermore, the elastic inlay is worn very quickly due to the small length of the running surface of the cable roller in relation to the length of the steel cable and must thus be replaced frequently, which entails high maintenance costs.